Tuesday, December 4, 2007

Who Spotted the Threading Errors?

When I looked at the pictures I had taken of this first 8-blocks crackle sampling, one thing immediately jumped at me. Something I had not noticed in the weaving. Something I had not noticed in the computer drawdown. Here it is, with the black arrows pointing to the problems that caught my attention:

Those arrows point to places where the weft yarn skips over more warp ends than it ought to. I went back and looked at the computer drawdown. These skips are not there. Clearly I made a mistake in the actual threading. When I looked at my threading and my notes, however, I threaded exactly as I had printed the threading out. However......and this is a big however....

The error appears at the point where I end the last block of the repeated group of blocks and begin the first block of that group of blocks. And since I repeated the group of blocks three times, that error occurs two times.

Here is the threading for the end of the repeat:

4 1 4 2

Here is the threading for the beginning of the repeat:

3 1 4 1

It had looked to me like there would not be a problem here when I entered the threading blocks into my computer software. What I did not do, however, is write out the last block and the first block as they would appear together. And this is what I would have gotten, had bothered to do this instead of thinking I "knew it all:"

3 1 4 1 4 1 4 2

Now the error is obvious to me. There is a repetition of the 4 1 pair. That repetition destroys the crackle block structure at the point and results in an extra bit of weft going over the warp ends. To correct the matter, all I have to do is leave out two warp ends, one on 4 and one on 1. Doing that gives me:

3 1 4 1 4 2

The first four numbers (3 1 4 1) give me one unit of the first block. The second two numbers give me the last two threads of the last block. The entire unit of that block reads 1 4 2 4. So, the last unit of the last block and the first unit of the first block, when written out look like this:

3 1 4 1 / 4 2 4 1

The slash indicates the division between the two blocks. All is well.

Now I know I cannot trust my imagination to see what is going on in the threading. I must write it down.

No, I did not rethread. This is only a sample. And seeing these two errors over and over again as I weave will reinforce what I need to do from now on. Hopefully................!


Dorothy said...

There is so much to know about weaving. Maybe this hadn't happened to you before just out of good luck, and because of an accident you've got a different understand of working with blocks.

An issue I see here is that weaving software is a fast way to get designs worked out, but in terms of thorough preparation I suspect there's no substitute for the step-by-step approach you have to take when drafting by hand. Using software, it's quite possible to overlook things like this.

I recently forgot to check float lengths in a pattern. Although the top surface in an advanced twill I'd designed was fine there were some ridiculously long floats on the back - and I didn't realise until it was off the loom. I need to organise a mirror for looking under the cloth on the loom, as I've seen you recommend!

Leigh said...

Yay for samples! We all knew there was a good reason for them, *lol*. Anyway, I never would have noticed that error from my galloping horse.